Secure Storage of Notification Credentials

Some notification types like Slack need credentials in order to push a notification message.

Currently there is no support for storing secret attributes of notifications in a secure manner.

CONCEPT

Support storing credentials for Monasca notifications in Barbican. Monasca notification is extended to use the Barbican service for retrieving named secrets for notifications. The Monasca API is extended to support adding one or several names of secrets to a notification. Creation of those secrets probably should be a separate activity.